The present invention relates to an external combustion engine that combines the advantages of different types of piston and rotary engines, and even of gas turbines, into a single construction arranged in a manner such that the free piston never makes solid contact with the sleeve while operating.
Diesel and Otto Cycle engines produce undesirable vibrations and low frequency noise. Diesel engines require high compression ratios and are difficult to start. Piston engines require the transformation of linear motion into circular motion, which is costly in terms of space and weight, thus they are heavy and necessarily bulky. The Wankel rotary engine has not held its anticipated promises, its lubrication being one cause of problems. Gas turbines require high rotation speeds, are small and light, but generate high pitch noises, are unefficient and expensive to manufacture. They do not appear practical for propulsion application to automobiles.
Thus efforts are needed and continuously being made to develop new and different engine concepts; engines which would be smaller, lighter, less particular in terms of fuel type and quality, long lasting, easy to start, exempt of cooling and/or lubricating problems. Being easy to operate, less expensive to manufacture and more efficient, and capable to burn a wide range of more easily available and less expensive fuels are additional enviable characteristics.
In view of this background, it is an object of the present invention to provide a new and improved combustion engine which combines the most advantageous construction features of the three types of engines mentioned above embodied into an efficient power plant which will operate equally well with various types of fuel under severe conditions and during a longer lifetime.
It is another object of the present invention to provide a slower combustion process to enhance burning efficiency, thus minimizing air pollution and allowing the use of less volatile and expensive fuels, possibly of a non-fossil nature, as methanol.
It is another object of the present invention to provide an improved power plant that is of simpler construction and with fewer and simpler moving parts.
It is another object of the present invention to provide a new and improved type of engine that produces lower noise and vibration levels for comparable power.
It is another object of the present invention to provide a new and improved power plant that is characterized by design flexibility for accomplishing optimizing objectives such as space and weight saving for easy adaptation to a specific application.
It is another object of the present invention to provide a new and improved engine in which friction losses are minimized, thereby easing lubrication and cooling requirements.
It is another object of the present invention to provide a new and inproved power plant in which a heat exchanger combined with a storage tank for compressed air and combusted gases may easily be installed between the combustion member and the power producing member.
It is another object of the present invention to provide a new and improved engine in which the mechanical segregation of the combustion member and of the power delivering member permits an optimum use of construction materials of a nature best suited for the specific component operation.
It is another object of the present invention to provide a new and improved power plant with enhanced overall reliability and in which maintenance and repair work is rendered easier and less complex and expensive.
It is another object of the present invention to provide a new and improved engine wherein the vibrations transmitted onto the engine mountings and the power shaft have lower levels and are of higher frequencies than is the case for conventional piston engines.
Finally it is still another object of the present invention to provide a new and improved engine in which the free reciprocating piston rides on pressurized compressed air cushions within its associated sleeve and the valving of the air and of the gas is automatic and requires no contact between piston and sleeve.